AMPforWP - AMP Cache for WordPress 2.2.15

* Bugs Fixed: =
* Resolved the issue of Warning: Trying to access array offset on value of type null.
* Resolved the issue of syntax error on the WooCommerce checkout page.
* Resolved the issue of missing slash in url.
* Resolved the issue of amp pages appearing blank.
* Resolved the issue of homepage cache not working properly.
* Resolved the issue of conflict with wprocket when amp takeover option is enabled.

* Bug Fixed: =* Resolved the issue of caching functionality with AMP Takeover Option does manually redirect to /amp.

* Resolved the issue of caching functionality not working with AMP Takeover Option.